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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 60 |
| 5 | 5040 |
| 6 | 3603600 |
| 7 | 908107200 |
| 8 | 15437822400 |
| 9 | 293318625600 |
| 10 | 267154604196480000 |
| 11 | 4935147003321575040000 |
| 12 | 1963886355464640647040000 |
| 13 | 74963506074440798138163840000 |
| 14 | 65039484811827775408882461490752000000 |
| 15 | 3415186532666352810621130006203072000000 |
[1,2,12,60,5040,3603600,908107200,15437822400, 293318625600,267154604196480000, 4935147003321575040000,1963886355464640647040000, 74963506074440798138163840000, 65039484811827775408882461490752000000, 3415186532666352810621130006203072000000] |